Previous studies have demonstrated that the interaction of CD40 on monocytes with CD40 ligand, present on activated CD4+ T cells, induces monocyte inflammatory cytokine synthesis and rescues monocytes from apoptosis. These findings suggest a role for CD40 signaling of monocyte activation in the maintenance and/or exacerbation of nonseptic (e.g., autoimmune) inflammatory responses. In the present study the effects of the modulatory cytokines IL-4 and IL-10 on CD40-mediated signaling of monocyte IL-1beta synthesis and rescue from apoptosis were examined. Both IL-4 and IL-10 decreased CD40-dependent IL-1beta synthesis in a dose-dependent manner individually and synergized in this effect when used concurrently, with minimal effect on CD40 surface expression. CD40 signaling of IL-1beta synthesis was shown to be dependent on the induction of protein tyrosine kinase (PTK) activity, and both IL-4 and IL-10 diminished CD40-mediated tyrosine phosphorylation of monocyte cellular proteins. However, IL-4, but not IL-10, blocked CD40-mediated rescue from apoptosis, an event that we have demonstrated previously to be dependent on PTK activity as well. Together these results suggest that in monocytes 1) both IL-4 and IL-10 target CD40-induced PTK activity in the down-regulation of IL-1beta synthesis; and 2) IL-4 and IL-10 have divergent effects on the CD40 signaling pathway, in that these cytokines are synergistic with respect to their abilities to inhibit CD40-mediated IL-1beta synthesis and differ in their abilities to block CD40-mediated rescue from apoptosis.

Chan Siu Lan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (leaves 149-181). / Abstracts in English and Chinese. / Abstract --- p.ii / Chinese Abstract (摘要) --- p.v / Acknowledgements --- p.viii / Publications --- p.x / Table of contents --- p.xii / List of Figures --- p.xvi / List of Table and Diagram --- p.xx / Abbreviations --- p.xxi / Chapter Chapter 1: --- Introduction / Chapter 1.1 --- Major objectives and long-term significance --- p.1 / Chapter 1.2 --- Biological significance of apoptosis --- p.1 / Chapter 1.3 --- Importance of apoptosis in the study of the female reproductive system --- p.3 / Chapter 1.4 --- Specific aims of the present project --- p.3 / Chapter 1.5 --- Experimental approaches --- p.8 / Chapter Chapter 2: --- Materials and Methods / Chapter 2.1 --- General experimental methods --- p.11 / Chapter 2.1.1 --- Culture of cells --- p.11 / Chapter 2.1.1.1 --- Culture of rabbit immortalized uterine epithelial cells --- p.11 / Chapter 2.1.1.2 --- Culture of primary mouse uterine epithelial cells --- p.12 / Chapter 2.1.1.3 --- Culture of human ovarian epithelial cancer cells --- p.13 / Chapter 2.1.2 --- Assessment of apoptotic DNA fragmentation --- p.13 / Chapter 2.1.2.1 --- DNA extraction --- p.14 / Chapter 2.1.2.2 --- Assessment of apoptotic DNA --- p.14 / Chapter 2.1.2.3 --- Assessment of apoptotic DNA by CE-LIF --- p.15 / Chapter 2.1.2.4 --- Assessment of apoptosis by Nuclear Hoechst 33248 Staining / Chapter 2.1.3 --- Assessement of protein content --- p.16 / Chapter 2.1.3.1 --- Protein extraction and western blot analysis --- p.16 / Chapter 2.1.4 --- Adenoviral infection of A2780s cells --- p.18 / Chapter 2.2 --- Preparation of solutions --- p.18 / Chapter 2.3 --- Animals and cell lines --- p.25 / Chapter 2.4 --- Statistical analysis --- p.25 / Chapter Chapter 3: --- Literature Review / Chapter 3.1 --- Morphological analysis of physiological cell death --- p.26 / Chapter 3.1.1 --- Characteristics of apoptosis --- p.27 / Chapter 3.2 --- Methods of detecting apoptosis --- p.31 / Chapter 3.3 --- Molecules controlling apoptosis --- p.33 / Chapter 3.3.1 --- Caspases --- p.33 / Chapter 3.3.2 --- The Bcl-2 family proteins --- p.34 / Chapter 3.4 --- Apoptosis signalling --- p.36 / Chapter 3.4.1 --- The death receptor-dependent pathway --- p.36 / Chapter 3.4.2 --- The mitochondria-dependent pathway --- p.38 / Chapter 3.4.3 --- The endoplasmic-reticulum-dependent pathway --- p.39 / Chapter 3.5 --- Importance of apoptosis in the female reproductive system --- p.40 / Chapter 3.5.1 --- Apoptosis in uterus epithelial cells --- p.40 / Chapter 3.5.2 --- Apoptosis in ovarian cancer cells --- p.42 / Chapter 3.6 --- Regulation of apoptosis by nitric oxide/cGMP/protein kinase G --- p.44 / Chapter 3.6.1 --- Regulation of apoptosis by nitric oxide --- p.44 / Chapter 3.6.2 --- Regulation of apoptosis by cGMP --- p.48 / Chapter 3.6.3 --- Regulation of apoptosis by soluble guanyly cyclase activator --- p.50 / Chapter Chapter 4: --- "Apoptotic DNA fragmentation caused by sodium nitroprusside, a nitric oxide donor, in uterine epithelial cells: ultrasensitive quantitation using the new capillary electrophoresis/laser-induced fluorescence (CE-LIF) technology" / Chapter 4.1 --- Abstract --- p.52 / Chapter 4.2 --- Introduction --- p.53 / Chapter 4.3 --- Results --- p.57 / Chapter 4.4 --- Discussion --- p.61 / Chapter 4.5 --- Figures of Chapter 4 --- p.66 / Chapter Chapter 5: --- Guanylyl-cyclase inhibitors NS2028 and ODQ and protein-kinase-G inhibitor KT5823 trigger apoptotic DNA fragmentation in an immortalized uterine epithelial cell line: anti-apoptotic effects of basal cGMP/PKG / Chapter 5.1 --- Abstract --- p.74 / Chapter 5.2 --- Introduction --- p.75 / Chapter 5.3 --- Results --- p.80 / Chapter 5.4 --- Discussion --- p.83 / Chapter 5.5 --- Figures of Chapter 5 --- p.89 / Chapter Chapter 6: --- "Direct, prolonged activation of soluble guanylyl cyclase by YC-1 or protein kinase G by cGMP analogs enhances the level of apoptosis in an immortalized uterine epithelial cell line, HRE-H9 cells" / Chapter 6.1 --- Abstract --- p.100 / Chapter 6.2 --- Introduction --- p.101 / Chapter 6.3 --- Results --- p.105 / Chapter 6.4 --- Discussion --- p.107 / Chapter 6.5 --- Figures of Chapter 6 --- p.114 / Chapter Chapter 7: --- "ODQ，an inhibitor of soluble guanylyl cyclase, down-regulates XIAP expression and induces apoptosis in human ovarian cancer cells" / Chapter 7.1 --- Abstract --- p.124 / Chapter 7.2 --- Introduction --- p.125 / Chapter 7.3 --- Results --- p.129 / Chapter 7.4 --- Discussion --- p.132 / Chapter 7.5 --- Figures of Chapter 7 --- p.138 / Chapter Chapter 8: --- Overall Conclusion --- p.145 / Chapter Chapter 9: --- References --- p.149

Hyperphosphorylated tau plays an important role in the formation of neurofibrillary tangles in brains of patients with Alzheimer's disease (AD) and related tauopathies and is a crucial factor in the pathogenesis of these disorders. Though diverse kinases have been implicated in tau phosphorylation, protein phosphatase 2A (PP2A) seems to be the major tau phosphatase. Using murine primary neurons from wild-type and human tau transgenic mice, we show that the antidiabetic drug metformin induces PP2A activity and reduces tau phosphorylation at PP2A-dependent epitopes in vitro and in vivo. This tau dephosphorylating potency can be blocked entirely by the PP2A inhibitors okadaic acid and fostriecin, confirming that PP2A is an important mediator of the observed effects. Surprisingly, metformin effects on PP2A activity and tau phosphorylation seem to be independent of AMPK activation, because in our experiments (i) metformin induces PP2A activity before and at lower levels than AMPK activity and (ii) the AMPK activator AICAR does not influence the phosphorylation of tau at the sites analyzed. Affinity chromatography and immunoprecipitation experiments together with PP2A activity assays indicate that metformin interferes with the association of the catalytic subunit of PP2A (PP2Ac) to the so-called MID1-alpha4 protein complex, which regulates the degradation of PP2Ac and thereby influences PP2A activity. In summary, our data suggest a potential beneficial role of biguanides such as metformin in the prophylaxis and/or therapy of AD.

Resveratrol is a polyphenolic phytoestrogen that has been shown to exhibit potent anti-oxidant, anti-inflammatory, and anti-catabolic properties. Increased osteoclastic and decreased osteoblastic activities result in bone resorption and loss of bone mass. These changes have been implicated in pathological processes in rheumatoid arthritis and osteoporosis. Receptor activator of NF-kappaB ligand (RANKL), a member of the TNF superfamily, is a major mediator of bone loss. In this study, we investigated the effects of resveratrol on RANKL during bone morphogenesis in high density bone cultures in vitro. Untreated bone-derived cell cultures produced well organized bone-like structures with a bone-specific matrix. Treatment with RANKL induced formation of tartrate-resistant acid phosphatase-positive multinucleated cells that exhibited morphological features of osteoclasts. RANKL induced NF-kappaB activation, whereas pretreatment with resveratrol completely inhibited this activation and suppressed the activation of IkappaBalpha kinase and IkappaBalpha phosphorylation and degradation. RANKL up-regulated p300 (a histone acetyltransferase) expression, which, in turn, promoted acetylation of NF-kappaB. Resveratrol inhibited RANKL-induced acetylation and nuclear translocation of NF-kappaB in a time- and concentration-dependent manner. In addition, activation of Sirt-1 (a histone deacetylase) by resveratrol induced Sirt-1-p300 association in bone-derived and preosteoblastic cells, leading to deacetylation of RANKL-induced NF-kappaB, inhibition of NF-kappaB transcriptional activation, and osteoclastogenesis. Co-treatment with resveratrol activated the bone transcription factors Cbfa-1 and Sirt-1 and induced the formation of Sirt-1-Cbfa-1 complexes. Overall, these results demonstrate that resveratrol-activated Sirt-1 plays pivotal roles in regulating the balance between the osteoclastic versus osteoblastic activity result in bone formation in vitro thereby highlighting its therapeutic potential for treating osteoporosis and rheumatoid arthritis-related bone loss.